A device in an aircraft denotes a functional assembly that can include hardware elements and/or software elements. It can be, for example, the automatic pilot, a brake, a landing gear control system, etc. Each device can be identified by two references: the type of device (or FIN, functional item number), and the serial number of the aircraft in which it is installed.
The same device can exist in different variants called versions or standards. The versions differ from one another by one or more hardware and/or software differences. The version of a device is also called P/N (part number).
Throughout the life of an aircraft, a device of the aircraft is modified numerous times. Each modification of the device is called an update, and causes the version or “P/N” of the device to change. An update can be specified by a transition from an earlier version to a later version of the device.
An update performed before delivery of the aircraft is generally stored in a so-called MOD file. A MOD file notably comprises a reference of the MOD file, an identifier of the earlier version, and an identifier of the later version. It can also contain a detail on the possibility of modifying the update (for example to modify the later version), and a date of last modification of the update. A pre-delivery update reference is formed, for example, by a MOD file reference, possibly accompanied by a date. For one type of device, and for several aircraft, one or more databases store lists of updates implemented in succession, before delivery of the aircraft (ECDB and ICC databases).
An update performed after delivery of the aircraft is generally stored in a file called SB, standing for “Service Bulletin”. An SB file notably comprises a reference of the SB file, an identifier of the earlier version, and an identifier of the later version. It can also contain a date of creation or of last modification. A post-delivery update reference is formed, for example, by an SB file reference, possibly accompanied by a date. For one type of device, and for several aircraft, one or more databases store a list of updates implemented in succession, after delivery of the aircraft (SB Comp database).